PDF Tools (Mac)

The Mac has some built-in tools for dealing with PDF documents. You can convert almost any document to PDF format by 'printing' it, clicking on the 'PDF' button at the bottom of the Print window and choosing 'Save as PDF'. You can open a PDF simply by double clicking on it, and it will be displayed in the 'Preview' application built into OS-X.

If you have a recent version of OS X (10.5 'Leopard', 10.6 'Snow Leopard' or 10.7 'Lion') then the Preview application can also be used to edit PDF documents. You can add pages by dragging them from the desktop straight into the 'tray' at the side of the main window, you can re-order pages by dragging them around the same side-bar, and you can delete pages by highlighting their icons in the side-bar and deleting them via the Edit menu.

If you are using an older version of OS X, however, things are not so simple. The most commonly required function is a way to combine several PDFs into one, which all the applications listed below can do. Some of them offer additional functions.

Free software

PDF Split and Merge, or PDFsam can do what its name suggests - it can merge several PDFs into a single document, and it can split a multipage PDF into separate documents. It can be downloaded from HERE. An 'enhanced' version is available for a donation
of 1€ or more, and offers a few more options.

Online tool: You can also join PDFs online at http://www.pdfjoin.com/ .
This would be convenient for very ocassional use, but less so for regular users or long documents.

Paid-for alternatives

If PDFsam doesn't work for you, here are some other options (in all cases, you can download a trial version before paying out for the
full product):